Briefcase downloads not working since 5.0.13 upgrade

This past weekend we upgraded from 5.0.4 to 5.0.13 (both Network editions). In 5.0.4 the Briefcase worked fine, but since the upgrade you can see all of your docs but when you click on them a new browser window reloads and puts you back into the Inbox. Even if you manually type the url the page still reloads and dumps you out at the Inbox. If you right click on the file and attempt to download the link you get a (random char set).htm.part file. I saw a similar post in 'Installations' but no one ever responded.

We have a case open with support, but I thought I would come appeal here to see if anyone had seen it.